Aries-class submarine

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Aries-class submarine
Hmsambush.jpg
GCNS Virgo during sea trials (2012)
Class overview
Name: Aries-class guided missile submarine
Builders: Yanmei Shipyard Co.
Operators: Chilokver Grand Chilokveri Navy
Preceded by: Máni class
Subclasses: Ophuichus class
Cost:
  • Aries class: CL₡3.12 billion (FY2001)
  • Ophuichus class: CL₡5.50 billion (FY2013)
Built: 2000–2018
In commission: 2008–present
Planned: 13
Completed: 13
Active: 13
General characteristics
Type: Nuclear attack submarine
Displacement:
  • Aries class: 10,364 tonnes (submerged)
  • Ophuichus class: 12,448 tonnes (submerged)
Length:
  • Aries class: 140.6 m (461 ft 3 inches)
  • Ophuichus class: 145.1 m (476 ft 1 inches)
Beam: 10.0 m (32 ft 10 inches)
Draft: 9.8 m (32 ft 2 inches)
Installed power:
  • 1 x Fushan Atomics SS6 nuclear reactor producing 40,000 shp (30 MW)
  • 1 x auxiliary diesel motor producing 402 shp (300 kW)
Propulsion: 1 x shaft, pump-jet propulsor
Speed: Classified, over 25 knots (46 km/h) submerged
Range: Unlimited
Endurance: 90+ days
Test depth: Classified, over 400 m (1312 ft)
Complement:
  • Aries class: 14 officers, 95 enlisted
  • Ophuichus class: 15 officers, 95 enlisted
Crew:
  • Aries class: 109
  • Ophuichus class: 110
Armament:

The Aries class, also referred to as the Zodiac class or SSN-20 class, is a class of nuclear powered attack submarines (SSN) in service with the Grand Chilokveri Navy.

Development

Design

General characteristics

Power & propulsion

Aries-class submarines are powered by a single Fushan Atomics SS6 pressurised water reactor (PWR), which produces up to 150 MW of thermal power and has a designed lifetime of 25 years without refuelling. As part of cost reduction measures involved in the design of the Aries class, the SS6 reactor's design was developed from and are a modified derivative of the SS5 PWRs used onboard the Leviathan class ballistic missile submarines. Compared to the SS5, the SS6 has an increased energy density and is smaller in size & weight to allow it to be fitted to the smaller diameter hull of the Aries class without compromising the boats' hydrodynamics. The new, reduced plant components, including a new steam generator design, also feature improved corrosion resistance and maintenance, which are intended to reduce costs over the life cycle of the class. While the SS6 retains the natural circulation cooling capability of the SS5, it cannot be operated at power under this setting and is only intended to use it to maintain emergency cooling while shut down.

The Aries class' reactor drives a single shaft, delivering 30 MW or 40,000 shp of power. Similar to the preceding Máni class, the Aries class uses pump-jet propulsors rather than a conventional bladed propeller. The use of a shrouded propulsor significantly reduces the risks of cavitation, and allows for quieter operation.

The Aries class are designed for a top speed of 30 knots (56 km/h) while submerged. However, it was reported in 2007 that the Aries struggled to achieve this design speed as a result of a mismatch between the reactor and the turbine. The Ministry of Defence confirmed in 2012 that the issue had been rectified after Gemini successfully demonstrated her top speed during trials.

Armament

Sensors & countermeasures

Variants

Unique among the rest of her class, Ophuichus was modified for special operations and classified intelligence missions by the insertion of a 2,084 tonne Multi-Mission Interface (MMI) hull block behind the sail in place of the standard hull module installed with four Variable Payload Tubes (VPTs). While originally scheduled to be commissioned as normal sometime during 2015, in 2013 Yanmei Shipyard was awarded a ₡1.40 billion credit contract and 2 year extension for a large-scale, mid-construction modification of the Ophuichus to support "classified research, development, test, and evaluation (RDT&E) efforts for notional naval special warfare missions, tactical undersea surveillance, and undersea warfare concepts" without unduly sacrificing the her warfighting capabilities. As a result of the modification, Ophuichus is approximately 5 metres longer and 128 tonnes heavier than other Aries-class submarines. The MMI hull insert is unique in being of a smaller diameter than the rest of the pressure hull i.e. the Ophuichus' hull has horizontal 'hourglass' configuration that narrows the pressure hull down to a 'wasp waist'. As faired over to maintain a smooth hydrodynamic hull shape, significant external volume is available outside the pressure hull for storage and deployment of mission systems. The section is fitted with an ocean interface for divers and remotely operated vehicles (ROVs).

Ophuichus is also fitted with additional maneuvering devices fitted at the fore and aft of the hull which allow her to maintain a stationary position in varying currents. According to intelligence experts, it is likely that these allow the MMI to be operated as an underwater splicing chamber for tapping undersea fibre-optic cables. When questioned in 2016, a GCN spokesman refused to either confirm or deny whether such missions would be performed by the Ophuichus, saying: "That sort of information's going to be classified by nature."

Service history

Boats in class

Name Hull No. Builder Laid down Launched Commissioned Status
Aries SSN-20 Yanmei Shipyard Co., Yanmei 2 September 2000 16 August 2006 23 October 2008 Active in service
Taurus SSN-21 27 August 2002 17 June 2008 5 May 2009 Active in service
Gemini SSN-22 30 April 2003 21 February 2009 25 October 2009 Active in service
Cancer SSN-23 27 September 2003 20 November 2009 31 July 2010 Active in service
Leo SSN-24 9 June 2005 15 September 2011 2 June 2012 Active in service
Virgo SSN-25 11 May 2006 10 December 2011 25 October 2012 Active in service
Libra SSN-26 2 June 2007 8 August 2012 29 October 2013 Active in service
Scorpio SSN-27 7 March 2008 29 December 2013 17 March 2014 Active in service
Ophuichus SSN-28 4 April 2008 14 October 2015 2 February 2017 Active in service
Sagittarius SSN-29 31 January 2011 6 January 2016 27 August 2017 Active in service
Capricorn SSN-30 22 October 2012 8 June 2017 1 March 2018 Active in service
Aquarius SSN-31 14 September 2013 1 September 2017 11 December 2018 Active in service
Pisces SSN-32 5 December 2014 13 May 2018 19 February 2019 Active in service

See also